Comments, observations and thoughts from two left coast bloggers on applied statistics, higher education and epidemiology. Joseph is a new assistant professor. Mark is a marketing statistician and former math teacher.

Thursday, April 21, 2011

Not much posting this weekend but I did have to take a moment to make the point in the subject line. This might seem too obvious to bother with but the otherwise very smart people at naked capitalism missed it.

The Food and Drug Administration has issued a caveat today, reminding consumers that any hand sanitizer or antiseptic product claiming to be effective against antibiotic-resistant infection is telling you a Bald. Faced. Lie.

No. They're. Not.

This is a complicated issue and our resident expert is otherwise occupied but I think I can lay out the basics. Rubbing alcohol and chlorine bleach both do well against MRSA and other antibiotic-resistant strains. We can get into a discussion of acceptable wording here which is what the FDA was getting at (admittedly in a poorly written statement) and we can talk about side effects, but if the active ingredient of a product is alcohol or bleach then it probably is effective.

How about hand sanitizers specifically? Wikipedia has a good summary (emphasis added):

The Centers for Disease Control says the most important way to prevent the transmission of dangerous diseases is to frequently wash your hands with soap and water and/or use a hand sanitizer. If soap and water are not available it is recommended to use a hand sanitizer that contains at least 60 percent alcohol.[16][17] Alcohol rubs kill many different kinds of bacteria, including antibiotic resistant bacteria and TB bacteria. It also has high viricidal activity against many different kinds of viruses, including enveloped viruses such as the flu virus, the common cold virus, and HIV, though is notably ineffective against the rabies virus.[18] [19] [20] Alcohol rub sanitizers are not very effective against Norovirus (winter vomiting virus) unless they are combined with benzalkonium chloride in a hand sanitizer.[21] Alcohol rubs also kill fungi.[22] University of Virginia Medical School researchers concluded that hand sanitizing is more effective against fighting the common cold than hand washing.[23] Alcohol kills both pathogenic (disease causing) microorganisms as well as resident bacterial flora, which generally do not cause illness. [24] Research shows that alcohol hand sanitizers do not pose any risk by eliminating "good" germs that are naturally present on the skin. The body quickly replenishes the good germs on the hands, often moving them in from just up the arms where there are fewer harmful germs.[25] Alcohol also strips the skin of the outer layer of oil, which may have negative effects on barrier function of the skin. However, washing with detergents, such as commonly used hand soaps, results in a greater barrier disruption of skin compared to alcohol solutions, suggesting a increased loss of skin lipids.[26] [27]